Stiffening material



STIFFENING MATERIAL Filed Aug. 19, 1933 High/1 Porous Deposlf ofPrec/P/i'afed Collold zl Mm er/al 6. Cellulose Edie-r l NVENTOR EARLE H.CAMERQN 4M. ATTOIQN I Patented Jan. 14, 1936 UNITED STATES PATENT OFFICESTIFFENING MATERIAL Earle H. Cameron, Caldwell, N. J., assignor to TheCelastic Corporation, Wilmington, Del., a corporation of DelawareApplication August 19, 1933, Serial No. 685,909 13 Claims. (01.12am)This invention relates to stifiening material and particularly to animproved material of the general type disclosed in United States Patent1,256,240, Lovell, February 12, 1918. Although not restricted to suchuse, material of the present type finds advantageous application asstiffeningmaterial for boots and shoes, such as fabric, patent leather,cut-out, or perforated boots and shoes, and therefore is described withmore particular reference to the boot and shoe industry.

Material of the Lovell type comprises a base fabric such as a wovenmaterial, for example cotton cloth, or a structureless material, forexample felt or paper, with"'its interstices carrying a precipitatedcolloidal material in a highly porous form termed .powdered by Lovell,such as a cellulosic derivative, casein, albumin and various gum andresins. In use, the fabric is immersed in a solvent for the precipitatedmate,- rial, thereby to resolve the same into a coalescent flaccidcondition, and when the material is in this condition the fabric isapplied in the lasting operations, shaped, and allowed to harden, byevaporation of solvent, in its shaped condition. While material of theLovell type is highly satisfactory in use, it sometimes gives rise tothe difficulty that'the colloidal matter becomes so soft and mushy whenthe stiffener is dipped into the solvent, that the colloidal matter canbe forced through the upper of a, shoe of fabric or similar material,during the lasting operations, thereby staining, disfiguring and ruiningthe upper; and similarly, the coating on a patent leather shoe upperwill be affected and softenedduring the lasting operations so that thecoating will be peeled from the leather, thereby damaging the upper;and, again, in lasting shoes having out-outs or perforations in theupper, the colloidal matter may be forced through the cutouts orperforations.

I have now devised a stiffening material of the general Lovell typewhich, in itself, overcomes the difficulties mentioned, and have alsodevised a method for the manufacture of such material.

In the accompanying drawing, the figure is a highly conventionalexaggerated cross sectional view of stiffening material made inaccordance with the present invention and embodying the presentinvention.

One object of my invention is to provide a stiffening material of thementioned and other desirable characteristics. A further object is toprovide a method for the production of such ma- 5 These objects areaccomplished by treating the stiffening material of the Lovell type, andtherefore havingits'entire content of colloidal material in precipitatedform, in such a way that the colloidal material is dissolved (althoughnot permanently removed from the fabric) and then re-deposited (orattached) on the fabric in such a. Way that a part of the deposit is incolloidal form, as distinguished from a precipitated form, but theremainder of the deposit is in a'precipitated form. As the colloidalmatter, in the fabric after treatment, is not entirely in a precipitatedor highly porous condition, it does not absorb the solvent, with whichthe fabric is ultimately treated for its use in the lasting operation,as quickly or in such a large amount as would the ordinary Lovellmaterial and, therefore, does not become as mushy as would the originalmaterial. Yet, on the other hand, it will absorb enough solvent so thatit will soften quicker than material prepared merely by subjecting. afabric impregnated with a cellulosic derivative dope to an air dryingoperation, e. g. that type of material known as the air dried colloidedstifiener. Thus the present material overcomes the disadvantages of theordinary stiffening materialwith precipitated colloidal matter whileretaining the fundamental advantages of such ma terial.

Specifically, the stiffening material is treated in a solvent bathcontaining a precipitation-restraining agent that is immiscible or butpartially miscible in a. following bath in which the material is to beimmersed for the purpose of precipitating colloidal material dissolvedby the first bath. The said agent may be either a solvent or anon-solvent for the colloidal material. Whether the agent be a solventor a non-solvent, its primary characteristic is that it is immiscible orat most only partially miscible with the pre- 'cipitating bath, asotherwisethere would be complete precipitation in the following bath.

When the solvent bath is composed of only a single ingredient, thisingredient must not only be a restraining agent but must also be asolvent and be partially miscible in the following bath. When thesolvent bath comprises more than one ingredient, the restraininggagentneed not be a solvent, provided one of the other ingredients present isa solvent; and, furthermore this ingredient that is a solvent may beentirely miscible in the following bath since the agent furnishes thefactor of immiscibility called for. The pre cipitating liquid in theprecipitating following bath tends to immediately and completelydisplace the solvent-bath liquid to the extent that that liquid ismiscible in the following bath; but, to the extent that that liquid isimmiscible in the following bath it restrains its own immediate orcomplete displacement, and thereby to that extent prevents theprecipitation of a partof the colloidal matter. Y

'After treatment, the fabric is dried, e. g. air dried, whereupon thatpart of the colloidal matter whose precipitation has been prevented andwhich has consequently been deposited during the process of air dryingby evaporative removal of solvent therefrom, will be in a harder andmore colloided form than before treatment.

In the use of the fabric, blanks of suitable shape may be cut therefrom.These are dipped into a suitable solvent, e.-g. diacetone alcohol andethyl alcohol which will render the blank soft enough to conform to thedesired shape. The colloidal matter is re-dissolved, into a coalescentflaccid body which may be placed and conformed into the desired shapeand will dry in the desired shape, stifi, flexible and resilient.

The particular colloidal matter and the stiffener to which the presentinvention is applicable may be, as above indicated, of many generaltypes. When of cellulosic derivative, it may be of cellulose ester, e.g. cellulose nitrate or cellulose acetate, or cellulose ether, e. g.ethyl cellulose or benzyl cellulose. The solvent for treatment inparticular accordance with the present invention will, of course, beselected for compatibility with the particular colloid in question.

For example, for the production of goods in accordance with theinvention, a Lovell material carrying cellulose nitrate in precipitatedform may be treated with a bath of (by volume) ethyl alcohol 90% andcastor oil 10%, and the precipitating bath be water since the castor oilis immiscible therewith. Material carrying cellulose acetate orcellulose nitrate in precipitated form may be treated with a bath of (byvolume) acetone and toluol 20% and the precipitating bath be water sincethe toluol is nearly immiscible therein. Material carrying celluloseacetate or cellulose nitrate in precipitated form may be treated with abath of (by volume) acetone 80% and ethyl acetate 20% and theprecipitating bath be water since the ethyl acetate is onlypartiallymiscible in the said bath. Material carrying cellulose acetate orcellulose nitrate in precipitated form may be treated with a bath ofethyl acetate (a solvent) and the precipitating bath be water sinceethyl acetate is only partially miscible in said bath. Material carryingethyl cellulose in precipitated form may be treated with a bath of (byvolume) acetone 80% and naphtha 20% and the precipitating bath be watersince the naphtha is nearly immiscible therein.

Other examples of mixtures of liquids that might be used for the solventbath are alcohol or acetone or methyl ethyl ketone etc. together withone or more of the following, ethyl acetate, castor oil, butyl alcohol,toluol, gasoline, butyl acetate, carbontetrachloride to be used inconnection with a precipitating bath of water.

The solvent bath, the precipitating bath, the times of immersiontherein, and such factors will, of course, be varied to meet theparticular conditions as will be understood by those skilled in the art.The time in the solvent bath must be so regulated that the solventaction is not prolonged sufliciently to not only dissolve but also toremove from the fabric the colloidal matter. The above examples aregiven merely as illustrations, as the percentages of the restrainingagent in the bath may be varied to meet the particular conditions.Generally speaking, for a Lovell material having e. g. flannel for abase and carrying about 6 ounces of precipitated cellulose nitrate persquare yard, I find that twelve seconds treatment with a mixturecontaining 80% ethyl alcohol and 20% toluol as mentioned above, followedby immersion in the art, these factors may be widely varied to meet thecircumstances of different particular cases.

While boots and shoes have been more particularly referred to, it willbe understood that stiifeners of the present type may be used in anyarticle of footwear, where the use recommends itself, and furthermore,may be used in any particular location desired as in the toe to form thebox or in the heel to form the counter.

As willbe evident the production of the stiffening material inaccordance with Lovell and its treatment in accordance with the presentinvention, may be carried on as a single continuous process.

I claim:

1. Method comprising treating a fabric whose interstices carry aprecipitated cellulose derivative, with a solvent-liquid to dissolve thecellulose derivative without removing it from the fabric, passing thefabric without drying into a precipitating bath, said solvent-liquid andsaid precipitating bath being at least partially immiscible and thefabric being subjected to said precipitating bath for a period of timeonly sufficient to precipitate part of the cellulose derivative. dryingthe fabric, and thereafter treating said fabric with a cellulosederivative solvent to soften it, shaping it, and allowing it to dry inthe desired final form.

2. Method comprising treating a fabric whose interstices carry aprecipitated cellulose derivative, with a solvent-liquid to dissolve thecellulose derivative without removing it from the fabric, saidsolvent-liquid comprising a water-soluble solvent for the cellulosederivative and a waterimmiscible liquid, passing the fabric withoutdrying into a water bath, the fabric being subjected to said water bathfor a period of time only sufficient to precipitate part of thecellulose derivative, drying "the fabric, and thereafter treating saidfabric with a cellulose derivative solvent to soften it, shaping it, andallowing it to dry in the desired final form. 7 v

3. Method comprising treating a fabric whose interstices carryprecipitated cellulose nitrate, with a solvent-liquid to dissolve thecellulose nitrate without removing it from the fabric, passing thefabric without drying into a precipitating bath, said solvent-liquid andsaid precipitating bath being at least partially immiscible, the

fabric being subjected to said precipitating bath (5 for a period oftime only suflicient to precipitate part of the cellulose nitrate,drying the fabric, and thereafter treating said fabric with a cellulosenitrate solvent to soften it, shaping it, and

I allowing it to dry in the desired final form.

4. Method Comprising treating a fabric whose interstices carryprecipitated cellulose nitrate, with a solvent-liquid to dissolve thecellulose nitrate without removing it from the fabric, saidsolvent-liquid comprising a water-soluble solvent for the cellulosenitrate and a water-immiscible liquid, passing ,the fabric withoutdrying into a water bath, the fabric being subjected to said water bathfor a period of time only sufficient to precipitate part ofthe cellulosenitrate, drying the fabric, and thereafter treating said fabric with acellulose nitrate solvent to soften it, shaping it, and allowing it todry in the desired final- "form. V

5.. Method comprising treating a fabric whose interstices carryprecipitated cellulose nitrate,

with a solvent-liquid to dissolve the cellulose nitrate without removingit from the fabric, said solvent-liquid comprising a water-solublesolvent for the cellulose nitrate and a water-immiscible liquid from thegroup consisting of castor oil and toluolypassing; the fabric withoutdrying into a water bath, the fabric being subjected to said water bathfor a period of time only .sufiicient to precipitate part of thecellulose nitrate, drying the fabric, and thereafter treating. saidfabric with a cellulose nitrate solvent to'soften it, shapifng'it, andallowing it to dry-in the desired final orm. 6. Method comprisingtreating a fabric whose interstices carry precipitated celluloseacetate, with a solvent-liquid to dissolve the cellulose acetate withoutremoving it from the fabric, said solvent-liquid comprising awater-soluble solvent form.

for the cellulose acetate and a water-immiscible liquid, passing thefabric without drying into a water bath, the fabric being subjected tosaid 7 water bath for a period oftime only sufficientto precipitate partof the cellulose acetate, dry

ing the fabric,and thereafter treating said fabricwith acelluloseacetate solvent to soften it, shaping it, and allowing it to dry in thedesired final 7. Method comprising treating a fabric whose intersticescarryprecipitated cellulose ether, with a solvent-liquid to .dissolvethe cellulose ether without removing it from the fabric, saidsolventliquid comprising a water-soluble solvent for the cellulose etherand a water-immiscible liquid, passing the fabric without drying into awater bath, the fabric being subjected to said water bath for a periodof time-only suflicient to precipitate part of the cellulose ether,drying the fabric, and thereafter treatingsaid fabric with a celluloseether solvent to soften it, shaping it, and allowing it to dry in thedesired final form.

8. Method comprising treating a fabric whose interstices carryprecipitated ethyl cellulose, with a solvent liquid to dissolve theethyl cellulose without removing it from the fabric, said solvent liquidcomprising a water-soluble solvent for the ethyl cellulose and awater-immiscible liquid, passing the fabric without drying into a waterbath, the fabric being subjected to said water bath for a period of timeonly suflicient to precipitate part of the ethyl cellulose, drying thefabric, and thereafter treating said fabric with an ethyl cellulosesolvent to soften it, shaping it, and allowing it to dry in the desiredfinal form.

9. A stiffening blank comprising a fabric whose interstices carrycellulosic derivative in precipitated form, the fabric also carrying,distributed uniformly throughout the precipitated derivative,

cellulosic derivative in a relatively firmer, harder, colloided, andmore solvent-resistant form, said blank being adapted to be treated witha cellulose derivative solvent to soften same, and then shaped and driedin the desired final form.

10. A stifiening blank comprising a fabric whose interstices carrycellulose acetate in precipitated form, the fabric also carrying,distributed uniformly throughout the precipitated cellulose acetate,cellulose acetate in a relatively firmer, harder, colloided, and moresolvent-' resistant form, said blank being adapted to be treated with acellulose acetate solvent to soften same, and then shaped and dried inthedesired final form. r

' firmer, harder, colloided, and more solventresistant form, said blankbeing adapted to be treated with a cellulose ether solvent to softensame, and then shaped and dried in the desired final form.

13..A stiffening blank comprising a fabric whose interstices carry ethylcellulose in precipitated form, the fabric also carrying, dis tributeduniformly throughout the precipitated ethyl cellulose, ethyl cellulosein a relatively firmer, harder, colloided, and more solventresistantform, said blank being adapted to be treated with an ethyl cellulosesolvent to soften same, and then shaped and dried in the desired final.form.

,.E'AR. LEH.CAMERON.

